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E. B. PERRINE.

PNEUMATIC DESPATCH was SYSTEM.

APPLICATION FILED MAR. 4. I918.

1 ,308, 1 91. Patented July 1, 1919.

. Inventor Enmefffi Perr'z'rre THE COLUMBIA FLANUDIAPH 641-. WASHINGTON, D. c.

N T D ST TES PATENT 0pm).

EMMETT B. rename or MIivnEAroLIs, mnnnsorn. i

i rNE UMArrc-nssPArcH-TuBE' sYsrEM.

To all wkomit may concern:

Be known that I, EMMETT B. PERRINE, a citizen of the United States, residing at Minneapolis, in the county of Hennepin and State of Minnesota,-have invented certain new and useful Improvements in Pneumatic- Despatch-Tube: Systems, of which the following is a specification. M invention relates to a pneumatic despatc tube system in which carriers, suchas document or cash carriers, are conveyed through spaces of varying temperature or from one building to another through transmission tubes which have portions thereof extending through the air outside of the buildings. An object of my invention is to provide a system of this kind which will not be detrimentally affected on account of the varying temperatures and which will operate as effectively in cold weather as at other times. In systems of this kind which are now in use the air is taken into the transmission tubes directly from inside the buildings and this air usually contains considerable moisture while in the winter time it is much warmer and moister than the outside air. The consequence is that when this air passes through the portion of the tubes exposed to a low temperature or through the portion outside of the buildings in cold weather the moisture is condensed and the operation of the system seriously interfered with. Not only is the presence of moisture in the tubes objectionable, but it freezes in portions of the tubes thus exposed or outside the buildings and causes difficulty in regard to the carriers passing therethrough. The objectof my invention therefore is to provide means for avoiding this difliculty. I accomplish this result by supplying the system with comparatively dry air. If the system passes from one building to another, I preferably take this air from the atmosphere outside the buildings. The humidity of this cold air in winter is relatively low in comparison with the air in the buildings, but if this air were to be taken at the low temperature directly into the transmission tubes it would result in the tubes becoming coated with frost which would not be desirable. Therefore in the case where the system passes between buildings, I provide for warming this cold air near the point where it enters the build ing in which it is supplied to the system.

The full objects and advantages of my in- Specification of Letters Patent. Application filed March 4, 1913.

Patented July 1, 1919. Serial No. 220,115.

vention will appear in connection with the detail description thereof and are particularlypointed out in the claims.

Referring to the drawings whichillustrate my invention in one of 'its forms, the single figure designated as Figure 1 is a diagrammatic view mostly in vertical cross section. i

The drawing shows two buildings A and B separated by a space C. An air pump 2 of usual construction has its pressure side connected with one or more transmission tubes 4; and its suction side connected with one or more transmission tubes 6. At 8 is represented the inlet pipe leading from the outside air into the building A. Just beyond where this pipe enters the building it is expanded into a chamber 10, containing a heating coil 12 of such capacity as to sufliciently heat the cold air passing in contact therewith. From this chamber a pipe 14,

which is in efiecta continuation of the pipe 8, leads into the transmission tube 6 for supplying air to the transmission system which may be of the customary type having carrier inlets at 16 and 18 and carrier outlets at 20 and 22.

The advantages and operation of my improved system will be obvious from the foregoing description. The formation of moisture and ice in the transmission tubes is effectively prevented without any tendency for the tubes to become coated with frost. This system therefore operates as satisfactorily in cold weather as in warm weather, and, furthermore, provides for ventilating the building by the introduction of fresh air which is heated prior to its discharge into the buildings, in the case where the transmission tubes pass from one building to another.

I claim:

1. The process of conveying carriers through spaces of varying temperatures in a pneumatic despatch tube system which consists in taking the air for the system from a supply of cold air, heating the air before it enters the system, and then causing said air to circulate through. the system.

2. The process of conveying carriers from one building to another in a pneumatic 3. A pneumati despatch tube system comprising transmission tubes passing through the outside air between buildings, means for causing currents of air to pass through said tubes, means for supplying cold outside air to said system, and means for heating said air before it enters the system. a

4. A pneumatic despatch tube system comprising transmission tubes passing through the outside air between buildings,'means for causing currents of air to pass through said tubes, an inlet pipe leading from the outside air through the wall of .abnilding for supplying cold outside air to said system, and

a heater for said air interposed between said inlet pipe and said system.

5. A pneumatic despatch tube system comprising transmission tubes passing through the outside air between buildings, means for causing currents of air to pass through said tubes, an inlet pipe leading from the outside air through the wall of a building for supplying cold outside air to said system, a chamber in saidpipe, and a heating coil in said chamber.

In testimony whereof I hereunto aflix my signature. EMMETT B. PERRINE.

Gopies'of this-patent may be obtained'for-five-cents each, by addressing the Commissioner of Patents, Washington, D. G. 

